Fuel for a new agricultural revolution

The claim that EU biofuels policy is reducing greenhouse gas emissions (A biofuel policy can be sustainable, March 28) flies in the face of recent scientific papers on nitrous oxide emissions and land-use change. Ferran Tarradellas, the European commission's energy spokesman, also conveniently ignores the concerns that the commission's own Joint Research Centre raised in a recent report.

The EU wants so called "sustainability standards" to greenwash the mass-scale biofuel demand in Europe. Demand in the UK will be driven by the renewable transport fuel obligation (RTFO) that forces the mandatory blending of biofuel into the UK fuel system from April 15. However, the RTFO will not even have the pretence of standards until 2011, and a recent report from the Environmental Audit Committee said the proposed UK standards are "unlikely to prevent environmental damage from biofuels".

No credible proposal exists for how standards can prevent indirect impacts, or how they could be enforced. Common impacts of mass-scale biofuel production operate at a system level that standards can't measure: ecosystem destruction and accelerated global warming, not to mention land and human displacement created by massive monoculture agriculture and rising food prices. The biofuels industry is unlikely to ever be made environmentally and socially safe.

Ruth Kelly should suspend the RTFO before April 15 or be culpable for an unfolding environmental and social disaster. Further, the UK must strongly oppose EU plans for a 10% mandatory biofuel in the draft renewable energy directive, and plans even higher biofuel quotas in the new fuel quality directive. Dr Andrew Boswell and Almuth ErnstingCo-directors, biofuelwatch

Ferran Tarradellas needs to think more broadly and consider more up-to-date technologies before backing a policy based mainly on a 35% CO2 reduction and a sustainability clause. We need to consider: the serious political and social impacts of food-price inflation, in a world that is suffering from food shortages, when using food-chain feedstocks for biofuel production; the harmful effects of methane from landfill waste sites, most of which is released; the possibility of setting national photosynthesis targets which alert us to the need for natural CO2 capture.

Second-generation biofuel processes which generate ethanol from municipal waste will deal with the landfill methane problem. However, to make sure that these processes are introduced quickly we shall need to rethink the current carbon-trading and RTFO regimes. They are too closely allied to first-generation technology.John PickeringLabour Finance and Industry Group

Your article (Top scientists warn against rush to biofuel, March 25) highlights the misconceptions key decision makers have had of energy matters over the years. It is essential that politicians, scientists and the wider community engage more effectively to avoid the repetition of ad hoc directives that are not properly researched, and ultimately could be counterproductive.

There is no sound logic for the choice, made five years ago, for 5.75% use of biofuel in petrol and diesel for road vehicles by 2010. At the time of this decision it was known that the use of fertilisers, coupled with harvesting, manufacturing and distribution, all drawing on fossil fuels, would limit significantly the net benefits of the biofuel route in reducing the carbon footprint of transportation.

Furthermore, natural photosynthesis is an extremely inefficient process for transforming the sun's energy into liquid fuel. The typical yield of 4 tonnes of biofuel per hectare per year represents less than 1% of the sunlight absorbed by the Earth's surface. The 80 tonnes of kerosene used for a one-way commercial flight across the Atlantic is equivalent to the annual biofuel yield from an area of approximately 30 football pitches.

The way ahead has to include research into increasing biofuel yields by at least an order of magnitude and investigating artificial photosynthesis for alcohol production, but also placing higher priority on other, much more efficient technologies. Photovoltaic cells raise the prospect of converting 20% of the sun's energy, and concentrated solar power devices still more. Coupled with a new generation of high-capacity electric batteries and hydrogen storage devices (using this gas from the electrolysis of water), this will provide the longer-term solution for vehicles at a fraction of the biofuel use of land. Future historians may ultimately see the biofuels of the early 21st century as a technological dead end. We need to promote more effectively now the alternatives to these.Dr Richard PikeChief executive, Royal Society of Chemistry

Alternatives such as light, energy-dense batteries are still some way off. Biofuel might therefore be considered a transitional technology to reduce fossil-fuel dependence in transport. However, the use of plants to make organic chemicals will be necessary and permanent, and it is likely that a component of our electrical supply will derive from plant combustion. The use of plants to supply liquid fuel in the medium term and chemicals and energy in the long term is therefore necessary and inevitable.

Recent concerns about biofuel crops relate to the release of carbon stored in land cleared to make way for energy crops. The same occurs when land is cleared for food crops, so these models tell us we are in deep trouble whether or not we produce biofuels. However, these calculations assume that agricultural land globally is close to the limits of its productivity. This is simply not the case.

The challenge we must embrace is to develop the crops, agricultural practices and processes that will supply food, energy, materials and chemicals in a manner that is economically, environmentally and socially sustainable. This will be the 21st century's agricultural revolution.Richard Templer and Jeremy WoodsPorter Alliance for Bioenergy Research, Imperial College